When using primusrun to launch Steam or any Steam game, the following information is known: - The application launches without an issue. - The output of /proc/acpi/bbswitch remains "OFF" - The performance of the application remains the same as if it were launched normally, i.e. it is running on Intel HD integrated graphics.

When primusrun is used to launch glxspheres: - The performance is significantly better than the integrated graphics card. - glxspheres acknowledges the the Nvidia card as its openGL renderer. - The output of /proc/acpi/bbswitch is "ON"

No matter what I do to try to launch TF2 using primusrun, it does not appear to use the dedicated card. It always appears to use the integrated graphics.

1) Is there any way to determine from within TF2 what card is being used? (Probably not)2) Should I disregard the /proc/acpi/bbswitch reading? (It is substantiated by the performance levels, so it's probably right)3) Is there something I'm missing about using primusrun?